Henry the Navigator And the Apollo Project That Launched Columbus by Ti mothy Rush

C olumbus's voyage across the Atlantic in 1492 was the westward application of the Apollo Project of the Renaissance : the coordinated advances in naviga­

tion, shipbu i lding, astronomy, and mapmaking, pioneered by Prince Henry of Portugal as part of a world d iscovery and evangelization effort .

Before Henry's t ime (1394-1460) , any sustained capacity to conduct deep- ea ai l ing was several thousands of years in the past, a part of earlier, more technologically prim itive, seagoing cultures. After Henry, ocean navigation became a branch of science, a perfected, transmissible technology of universal potential .

Prince Henry, known to English speakers as "Henry the Navigator," devoted his l i fe to the accomplishment of this task. But his achievement wa possible only through the combined effort of the polit ical, rel igious, artistic, and scientific leader of the early Renaissance. Their role in wi l lfully shaping the conceptual breakthroughs necessary for this great project, and in educating a ski l led layer of the population to carry it through, wil l stand for al l t ime as one of humanity's finest accomplishments. The "science driver" project of Prince Henry and his ci rcles should be studied today by al l who seek to advance science and to overcome the cl imate of pessimism, fear, and i rrationality that again threatens to throw us back to a Dark Age.

'Have Dominion over the Seas' Henry's project was "to prove devotion to God by making

the seas navigable ," in the words of the 1455 Papal edict that raised Henry's efforts to a strategic priority for all Chris­tendom after the 1453 fall of Constantinople. For more than 100 years, since the time of Roger Bacon and Ramon lul l , a strategic plan for Ch ristianity to outflank the Venetian and Ottoman Turkish Empire's usu rious grip on the Eastern Mediterranean, by circumnavigating Africa, or heading west across the Atlantic, had been on the table. But the logistical and technological problems were staggering:

• The boats of the t ime, both gal leys and one-masted trading vessels, could not handle long voyages on the high seas.

• Navigation and nautical astronomy were not developed for routes outside the northern temperate zone and the Mediterranean .

• There was almost no knowledge of the complex winds and currents in the high seas.

• There was no first-hand knowledge of even the first 500 miles of African coast, let alone the remaining 8,000 mi les.

• Medieval superstition had many sai lors terrified that penetrating beyond the then-known l imits of ai l ing would be a suic ide mission .

The strategic plan languished for almost a century, while Spain and especially Portugal bui lt up important maritime capacities and an institutional framework for such an effort. The Iberian Peninsula was the corner of Europe in which an evangelizing mission and spirit of the Reconquista (the reassertion of Christian control over territory taken by the Moors) was most alive. This potential was brought to flow­ering during the 1400s, under constant nourishment from the organizing centers of the Renaissance, most especially Florence.

Did Poets launch the Caravels? What was the spark that reached over the 14th centu ry

to ignite the Portuguese maritime "breakout" of the 15th century ? Practical pol it ics ? A mere useful technology? What made this achievement possible were the activities of some of the greatest poeUdiplomats and other inte l lectuals of that-or any-age.

A plan to explore the Atlantic westward was fi rst advanced by the F ranciscan Roger Bacon (ca. 1214-1 294) in his Opus Majus. Bacon's proposal was copied word for word into Card inal Pierre D'Ail ly's Imago Mundi in the early 15th cen­tury-a book (and a passage) that became the most heavily annotated of all books in Columbus's l ibrary.

21 st CENTURY Summer 1 992 19

Stone statue of Henry the Navigator in the facade of the great monastery of Batalha, north of Lisbon. Henry's father Dom lotio I, erected Batalha to commemorate the battle at Aljubarrota, which initiated his reign (1385-7432). Prince Henry was buried there.

Ramon lul l ( 1232-1315) , the Catalan Franciscan scholar who battled against the Aristotelian/Averroist cu rrents of that time, introduced a broader strategic conception into the Council of Vienne, in 1 3 1 1 . I t was to move against Vene­tian-Turkish control by a pincers action : F i rst, to shatter the Western reach of Moslem power by taking Ceuta, the southern of the famed Pi l lars of Hercules at the outlet of the Mediterranean Sea to the Atlantic Ocean (the northern one being Gibraltar). Second, to circumnavigate Africa, to strike a blow di rectly into the hinterland of Moslem pow­er-the "Arabic lake" that later was called the Indian Ocean.

20 Summer 1 992 21 st CENTURY

Petrarch (1 304-1374) , successor poet laureate to Dante in the I talian vernacular, certainly seems to have promoted or recognized such a daring strategic conception. I n the midst of high-level diplomatic missions in the 1 340s and 1350s to end the F rench-English conflict that had rent the Western Christian world (what would later be called the Hundred Years' War) , Petrarch kept a close watch out for intell igence reports concern ing the rediscovery of the Canary Islands. located off the inhospitable northwest coast of Africa, these were the great Atlantic "way stat ions" to any large­scale exploration of the South Atlantic.

The poet and storyteller Giovanni Boccaccio (1313-1375), Petrarch's companion in the battle to rescue European civi­lization from the collapse of the Black Plague, wrote one of the great intell igence reports of the age on the 1341 expedition to the Canaries by Genoese merchants under Portuguese crown sponsorship.

I n 1 344 and 1 345, Portuguese King Afonso IV sent emissar­ies to the Pope to secure overseas exploration rights for his nation . Petrarch was watching the Venetian reaction closely. A modern historian comments : "Petrarch, when he saw Dom Afonso IV expanding over the ocean, while Venice and Genoa exhausted one another in jealous quar­rels, predicted that they [the Portuguese) would in the end destroy the very dominions that I taly possessed in the world" (Brochado, et a l . 1960) .

The spark can then be traced through England's great poet, Geoffrey Chaucer (ca . 1 340-1400). In the same de­cades in which he was ennobling the English language as a vehicle for Renaissance thought and conceptions, Chaucer served as England's chief ambassador to continental Eu­rope. From 1 372 to 1 380, he undertook seven major diplo­matic missions, including a celebrated meeting with Pe­trarch in 1 372. From I taly he brought back to England nu­merous volumes of Dante, Petrarch, and Boccaccio.

The Birth of Prince Henry From here the thread leads di rectly to Portugal and the

birth of Prince Henry. For the signal strategic accomplish­ment of Chaucer's patron and sponsor, John of Gaunt (the Duke of lancaster), was to cement a far-reaching strategic al l iance with the newly installed House of Avis in Portugal . As part of the al l iance-forged in seven days of intense diplomacy in 1 386 in a tent on the banks of the Minho River-John of Gaunt gave his eldest daughter, Phil ippa, in marriage to Dom Joao I of Portugal . The third son of this marriage was Prince Henry.

Henry's grandmother, John of Gaunt's wife Blanche, was immortalized in Chaucer's Canterbury Tales as the protago­nist of his HBook of the Duchesse. " It is also reported that Chaucer gave instruction in the use of the astrolabe and other scientific instruments to Grandmother Blanche and perhaps to Henry's mother, Ph i l ippa, as well .

Under the vigorous Dom Joao I , Portugal eagerly entered into al liance with factions in England, the Rhineland, the court of Holy Roman Emperor Sigismund in Vienna, and Florence. They were brought together by a determination to reu nite the Church, split by the Great Schism that saw rival Popes in Avignon and Rome; to contain the continuing

The assault on Ceuta, the stronghold opposite Gibraltar at the A tlantic outlet of the Mediterranean. Prince Henry and his two brothers aided their father Dom loao I in the taking of this fortress from the Moors in 14 15. Inset is a map of Portugal and the surrounding area.

N O R T H A F R I C A

French-English conflict; and to marshal al l of Western Christianity's efforts to repel the advancing Ottoman Turks.

Three Brother Princes Thus Joao l ied his eldest three sons, each having reached

manhood, to the reconquest of the city of Ceuta, in Moroc­co opposite Gibraltar, in August 141 5 . This was the first stage of the Lu l l project reaching back to 131 1 . The action was taken in synchronization with the then-meet ing Coun­cil of Constance, which at long last healed the split in the Church. I t is said that the news of Joao's victory at Ceuta "spread rapidly throughout the Ch ristian world and caused a tremendous sensation. When the good news arrived at Constance, prelates and princes expressed their admi ra­tion for Dom Joao I and his i l lustrious generation of sons" (Brochado, et a l . ) .

There was a clear division of labor among the princes. Eldest son Duarte, the heir to the throne, was a foremost intellectual , who wrote 22 treatises we know of, five on how to govern, and others on riding, fencing, and astronomy. Among these is a manual on govern ing based on his own family's upbringing, called Leal Conselheiro (the Loyal Ad­viser). The book shows that the princes held conversations on literary topics with thei r father and others and "discuss­ed rules and instructions for making good translations of classical works ."

The second brother, Pedro, covered the diplomatic flank of Portugal's emerging "Atlantic Strategy." In 1 425, he em­barked on a four-year mission through most of E u rope, which proved one of the widest and most successful d iplo-

matic and scientific expeditions of history. From E ngland, "where he was able to renew the cultural

ties of his own country with English scientific ci rcles" (Bro­chado, et al . ) , Pedro proceeds to the Flemish city of Bruges, the northern crossroads of the emerging Medici banking empire and the Hanseatic League. There he arranges the marriage of his sister Isabel to the Duke of Burgundy, who presided over one of the most powerful courts in E u rope.

After wintering in the Rhineland, he passes through N u r­emberg to arrive at Sigismund's court in Vienna. For more than two years, Pedro makes this his center of operations, participating repeatedly in mi l i tary campaigns of Sigis­mund's forces against the Ottoman hosts of Murad II in the lower and central Danube.

In the spring of 1 428, Pedro moves on to Italy. I n a visit worthy of a classical d rama, he spends two weeks as the honored guest of the Serenissima Repubblica of Venice­the common enemy of every faction he is al lied with and the treacherous oligarchical "brain of E u rope . " As the Doge (the Venetian ruler) fetes Pedro on the famous state galley, Bucintoro, the Venetians probed for Portuguese weakness­es-perhaps attempting to calculate what it might take to buy off Portugal .

Pedro leaves Venice with jewels worth more than 400 gold ducats, an original manuscript of Marco Polo's travels, and one of the latest world maps drafted by a Venetian cartographer. If this is what Venice thought could buy Por­tugal , i t clearly fai led. Pedro's next stop is Florence, initiat­ing one of the most far-reaching col laborations in h istory, which joins the emerging center of the Renaissance with

21 st CENTURY Summer 1 992 21

the supreme maritime power of the next 75 years.

Portugal and the Florentine Renaissance F lorence was the scientific center of the Renaissance.

Here, a c ircle of intel lectual collaborators and supporters of the " Atlantic strategy" al ready included Dom Gomes Fer­reira da Si lva, Portugal's "man in F lorence" since 1415. Da Si lva was admin istrator of a fund of 20,000 gold florins estab­l ished by Pedro's father, King Joao I , as a k ind of slush fund for special projects of the Portuguese ruling house. In fact, the enti rety of Pedro's fou r years of travel was paid from this fund, under Dom Gomes's supervision.

Gomes was prominent in the cir.cles who were to lead the bri l l iant diplomatic and cultural offensive that culmi­nated in the Council of Florence a decade later. Ch ief among these was the Camaldolese monk Ambrogio Traver­sari . In Traversari's room at the Convento degl i Angel i , an extraordinary group of hu manists was meeting to plan the projects of statecraft, art, and science that are synonymous with the Florentine Renaissance today. Foremost among them were Cosimo de' Medici , Palla Strozzi , and Paolo dal Pozzo Toscanel l i .

Upon h i s arrival , Pedro was t h e toast o f the city . A joust

FORMER NASA DEPUTY :

was held in his honor. Literary works were dedicated to h im. "The human ists made much of the Portuguese prince" writes Dos Passos (1%9). Among the aims of his mission was "to look for geographiC materials for Prince Henry his brother . . . " i ncluding geographic codices sent from Con­stantinople at the request of Antonio Corbinell i (Uziel l i 1892) . The high point came with the intense discussions Gomes arranges for Pedro with Traversari and his circle at the convent. These made such an impression on Traversari that he subsequently wrote a dedication to Pedro in the manuscript of one of his most important translation works.

Stopping in Rome on his way home, Pedro received ver­bal assu rances from the Pope that Portugal had full backing in its " Atlantic Strategy ." Within a year of his return , Pedro had cemented a commercial accord with Florence that would last a h undred years. I n 1 439, Pedro became regent of Portugal and de facto held the crown for eight of the most crucial years of Prince Henry's enterprise.

The Project Takes Shape The first voyages under Prince Henry's sponsorship be­

gan the year after the 1415 victory at Ceuta. Henry immedi­ately set up an intel l igence service to coordinate every scrap

' I Always relt the Ghost of Prince Henry Behind Us'

22

Dr. Hans Mark, former deputy director of the National Aeronautics and Space Administration, addressed the annual meeting of the American Association for the Ad­vancement of Science in February 1992 on "Henry the Navigator and the Early Days of Exploration. " Mark is currently chancellor of the University of Texas system. These are excerpts from his speech.

• • • For someone who has been involved in space explora­

tion for 20 years as I have, Prince Henry of Portugal has always occupied a special place. Henry was the instigator and sponsor of the first long overseas voyages by E u ro­peans that resulted in the sustained and systematic ex­ploration of the world . . . .

The "cape" from which Henry's captains launched thei r voyages was not cal led Canaveral but St. Vincent, the westernmost point in Europe . . . . Henry's own headquarters were located at Sagres, a small settlement overlooking the Cape, and it was here that he bui lt his research center by converting a smal l mi l i tary installa­tion that was a lready there. I t was here that he in­vented what is, perhaps, his most last ing contribution : the mission-oriented research and development institution . . . .

The mathematician and cartographer Pedro Nunes, who spent the early years of the 16th century as a profes­sor of mathematics at the University of Lisbon, was a disciple of Prince Henry. He undoubtedly visited Sag res

Summer 1 992 21 st CENTURY

many times d u ring his career. He says "from i toursai lors went out wel l taught and provided with instruments and rules which all map makers and navigators should know." These words are particularly significant because Professor N unes was there during the years that the insti­tution at Sagres was most influential .

These tantalizing words, al l written before the "mod­ern" technology and development institutions, such as the large government-sponsored laboratories around the world or the large research institutions of big indus­trial corporations, became familiar features of the scien­ti fic and technological landscape, indicate what must have happened . . . . What Henry did was to put together people who were expert in the basic sciences and who contributed to the increase of knowledge in these sci­ences with practitioners of the art of navigation . This combination turned out to be exceedingly successful . It has persisted to this day as the essential feature of how we do business in the technology development process.

. . . I have to confess that I always felt that the ghost of Prince Henry was standing behind successive NASA admin istrators in Washington as I worked for them. I am sure that he gu ided their thinking consciously or unconsciously. Those of us who carried out NASA's work in the field were l ike the captains who, 500 years ago, sailed down the coast of Africa, and in doing so, opened the most important vista that European cultu re has provided for the world.

of information he could glean from caravan traders, pi lots, and Jewish and Moslem travelers from across North Africa. He established within his own household a virtual t raining school for the mariners and explorers who would go forth for the next two generations in wider and wider arcs of discovery . And he began the methodical search for, and colonization of, islands in the Atlantic as "way stations" for the broader exploratory thrusts in the making.

Much modern historiography would have us believe that Henry and those who fol lowed his lead were simply gold­hungry and slave-hungry empi re-bui lders. The truth is that Henry's explorations were not fundamentally a commercial enterprise. They were completely un l ike the methods of looting developed by the Venetians and later embodied in the Dutch East I ndia and British East India companies. I n its later stages, Henry sought to recover the high costs of the project through commercial benefits, but his guiding mo­tives were religious and strategic.

Henry led a pious, ascetic l i fe in which his devotion to the Order of Christ was the driving force. Created by the great Portuguese King Diniz in the early 1 300s as the nation­al ized form of the collapsed Templar Order, the Order of Christ had assumed an extraordinary importance by the

Hans Mark, NASA deputy administrator, views a shuttle launch from the Johnson Space Center's mission control center, April 13, 1 983. Inset is the launch of Space Shuttle Discovery from Cape Ca­naveral, Sept. 29, 1988.

National Aeronautics and Space Administration

time of Henry's father, Joao I . At that time, as one commen­tator put it (Brochado, et a l . ) :

Both nationally and international ly, the only force worthy of account beside the throne was the Order of Christ ; and everything leads us to suppose that the Order was the structure of the state itself.

From the first substantial contact with sub-Saharan Afri­can populations in the early 1 440s to the end of the century, Henry's evangeliZing methods and di rectives guided the expanding contact with native populations. Although Hen­ry did not ban slavery (slavery was general ized throughout E u rope and Africa at the time as household slavery, and was run through Venice), he inst ructed that as many Africans be brought back to Portugal as possible, be instructed in Western Christianity and its languages, and be returned to their home to spread the gospel there. This approach bore remarkable fruit a generation later in the extraordinary Kingdom of the Kongo, a Christianized k ingdom in black Africa that survived for almost a century, from 1 490-1570.

Madeira As an Ocean 'Space Station' I f it can be said today that God made the Moon so man

could get to Mars, Henry could reasonably have concluded that God created the Canaries and Madeira islands so man could get past the Sahara and sai l the ocean seas.

There is probably no stretch of coast anywhere in the world as hosti le and nearly impervious to ocean-based ex­ploration as the Atlantic coast of northwest Africa. F rom Morocco to the Senegal River, a d istance of more than 1 ,500 miles, the Sahara joins with the sea . There is no place to get water or food, no harbors, only harsh winds and sand­storms reaching far out into the water.

The Madeira and Porto Santo, which Henry ordered re­discovered and colon ized in the 141 8-1420 period, were the opposite of the harsh main land : lush, richly watered lands that opened up excellent prospects for commercial devel­opment and permanent sett lement . There is no doubt that behind Henry's di rectives for the colon ization of the islands was the bigger plan, in which the new islands were but the first step in the discovery of new worlds. The first boy and girl born on Madeira were named Adam and Eve.

Henry now had his way-station, a place to take on new provisions, repair ships, and, if necessary, to wait for the proper winds . Yet it was not all clear sai l ing ahead.

Surmounting the Psychological Barrier Anyone first looking into Henry's "Atlantic Project" is

struck by the huge d isparity between what was ult imately accomplished by the project and the pitifu l ly meager ad­vances of the first 15 years. Even with the Madeira island way-station, the development of manpower and an in­house intell igence service, and the first steps in the assem­bling of a team of map-making and navigational experts, the tangible results were almost nonexistent. Henry had sent out ships 14 t imes over 15 sai l ing seasons before any of his captains had even rounded Cape Bojador, a point on the North African coast not very far beyond Moroccan cities that had been part of trade routes for hundreds of years.

21 st CENTURY Summer 1992 23

The d ifficu lty was as much psychological as physical . Cape Bojador, a promontory on the Mauritania coast so small that it is difficult to find on a map today, took on legendary characteristics as the "end of navigable sea . " A strong wind there had created a sand spit reaching far into the sea. Here the water was almost constantly chu rned into a froth, which seamen imagined to be " boi l ing. " Over the years the Arabic traders took advantage of these fears, exag­gerating the stories i n order to create terror among Chris­tian seamen, and thus protect the h interland of thei r cara­van routes from encroachment .

There was also the considerable problem of the prevail­ing winds. The passage down the coast from Portugal was favorable in almost al l seasons. This was the easternmost reach of the great circular movement of the northern hemi­sphere trade winds, moving clockwise and preparing to shoot across to the American continent a l i tt le south of the latitude of the Canaries. However, for exactly the same reason, the retu rn voyage to Portugal was laborious and hazardous, requ i ring constant tacking and maneuvering. A generation later, when the Portuguese had penetrated as far as Guinea, it was noted that " i f the winds were contrary (on the return) , it sometimes took four months, while one could go out in 20 days. "

I t was not unt i l 1 434 that Henry's most trusted captain, his shield-bearer Gi l Eannes, finally d rove beyond Bojador. It is reported that he tricked his crew, put the ship out to sea du ring the night to round the cape, and told them they were near the point only when they were beyond i t !

The way now lay open for a steady, sustained advance. But the further the progress, the more pressing the interre­lated questions of navigational, astronomical , and ship­building innovations would become. Henry would need a center of operations, a place at which he could concentrate his forces to create the needed breakthroughs and coordi­nate the resu lts: He needed a mission control. This is what has come down to us as the School of Sagres.

The Sagres Mission Control Center Sagres, a small promontory next to Cape St. Vincent at

the southwestern tip of the Iberian peninsula, was the headquarters of Henry's operat ion. There has been much recent controversy over whether the group of people Hen­ry assembled at Sag res constituted anything more than a glorified pi lots' school . What can be reconstructed with certainty goes far beyond this. Sagres-the Promontorium Sacrum, or Sacred Promontory, of Roman t imes-was the point of intersection for al l facets of Henry's project. These included :

• the intell igence-gathering machine; • the training for the voyages of the personnel within his

household ; • the revolutionary advances in ship design centering on

the caravel, carried out at the nearby Lagos shipyards bui l t and supervised by Henry;

• the design and execution of a colonization pol icy; • al l intermixed with a core group of resident cartogra­

phers, scientists, and geographers and a ceaseless stream of visitors from throughout the known world.

What a project tea m !

24 Summer 1 992 2 1 st CENTURY

At its center, the only cartographer in the group known by name was the Majorcan jew, jahuda (in Portuguese, jacome) Cresques. He brought a number of companions and all the papers of his great father, the Abraham Cresques known as "magister mappamundorum et buxolorum, " mas­ter of the world map and compass. Abraham had taught at Majorca's renowned school of navigation, mastered the manufacture of navigational instruments, perfected a series of tables to calculate sea distances, and designed the famed Catalan Atlas of 1 375, among many other cartographic achievements.

The Invention of the Caravel The development and introduction of the caravel under

Henry's sponsorship in the period around 1440 was one of the great technological leaps of the Renaissance. It was accompl ished with in a span of only five or ten years of two other great achievements of the age : Brunelleschi's successful arching of the 42-meter span under the dome of the cathedral of Santa Maria del Fiore in F lorence and the Western development of the printing press.

The need for a new ship design had become clear. Gal leys were out of the question for deep-sea ocean travel-the ratio of men to ship size wou ld have meant impossibly large requ i rements of food and water. The barca and va rine/, used by Henry in the early voyages, were heavy, round­bel l ied merchant ships and difficult to maneuver because they rode low in the water. They used just one mast and one large sai l .

Out o f Henry's shipyards came a n " intrinsically revolu­tionary vessel, with respect to both rigging and hull design. She was three-masted and usually lateen rigged" (Penrose 1952). The lateen sai l is cut in approximately the shape of a right triangle and hoisted up the mast near the center of the hypotenuse such that a segment flies forward of the mast (see i l l iustration, page 18) . The design is more l ike the modern Marconi rig of jib and mainsail than the square­rigged vessels that predominated from the 16th through 19th centu ries, and gives the ship a greater abil ity to go to windward. The ratio of beam to length was not 1 : 2, but 1 : 3 and even 1 :4 . As Penrose described it : " I t was thus the combination of hu l l , size, and rig that made the caravel far and away the most efficient sai l ing vessel built up to that t ime. Excellent in windward work, these ships cou ld sail anywhere but into the 'eye of the wind', while their daily runs in favorable weather sometimes rivaled the logs of the famous cl ipper ships of a later day . " The caravel was the standard ship of Colu mbus'S voyages.

The 'long Ocean Tack' The caravel opened one of the great deep-sea achieve­

ments of Henry's (or any later) t ime: what became known as the "Guinea Tack" or the " Long Ocean Tack . "

Examine closely the pattern o f winds and currents that the Portuguese had to contend with as they proceeded farther and farther down the African coast (F igure 1 ) . Down to approximately the 15th paral lel, at the "bulge" of Sene­gal , both wind and water cu rrents tend uniformly south and southwest. I t was l i terally a breeze out-and hell tacking back. Next came the problem of calms off the Sierra Leone

coast. (An I talian crew stayed becalmed in the area 57 days in 1503). Farther south , from the Cameroons a l l the way to the Cape of Good Hope, both winds and currents run against the south-bound mariner, while aiding the return.

The result was that any l inear conception of the explora­tion voyages was doomed . The longer the distance, the more the traditional method of coastal sai l ing undermined its own viabi lity. The time taken in tacking and waiting for favorable winds created many dangers : the lethal effects of tropical heat and diseases on the crews, tropical waters rotting out the wooden hul ls, and the sl immer and sl immer margins of provisions that could be carried for such long distances. All told, it meant that no sustained course of exploration, evangelization, or commerce could be carried out by relying on the old methods.

Henry's crews hit upon a unique, nonl inear solution . As the voyages probed farther and farther south, the captains began to set sail at an oblique angle to the contrary winds they faced heading home. They headed north and north­west. But instead of tacking a few miles, and then tacking back in the opposite d i rection, they kept going-for up to a thousand mi les of open ocean, unti l they reached the vicinity of the Azores. There they turned east, uti l izing the variable winds of that lat itude, which shuttled them, rela-

(a)

(b) L..-_--=:::""-__ --=-_--'.= .. -:::-.:-.J

Figure 1 THE LONG OCEAN TACK:

NON L I N EAR SOLUTION IN OCEAN SAI LING

Portuguese captains working in the tradition of the Sagres "Mission Center" discovered a way to make the trip around the tip of Africa in far less than the five months it took by arduous coastwise sailing into the prevailing southerly winds encountered below the Equator. Using their knowledge of the wind circulation patterns (aJ, they first sailed southwestward, crossed the equatorial dol­drums, and continued nearly to the Brazilian coast. They then cut southeast to round the Cape of Good Hope with the wind on their beam (b). Dotted line shows return.

tively securely, due east to Lisbon . The total distance of the two legs of this " long Ocean Tack" was substantially greater than the d i rect route, but the saving in time more than made up for i t .

Once the route is superimposed on wind and sea cur­rents, the configuration is an extraordi nary use of the natu­ral conditions as a booster. One is reminded of a more modern nonl inear navigational technique, the concept of "gravity-assist" used by NASA in propel l ing spacecraft to distant planets. The " J upiter sl ing," used to propel the U lys­ses spacecraft i nward to the Sun by first going out to Jupiter to gain gravitational acceleration, is a strik ing example. Sim­ilarly, the Gali leo mission , destined for J upiter, first flew twice around the Earth and out in the opposite di rection beyond the Moon, in order to pick up acceleration for the long trip to the fifth planet. The particular force to be reck­oned with is different, but the mode of solution the same. I n both cases, the most efficient path is not the one that is geometrically the shortest.

Onward to India Once coming u pon this solution , Henry's team then i n­

verted and extended it into the southern hemisphere to accomplish the great breakthrough of Vasco da Gama's

21 st CENTURY Summer 1 992 25

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STRABO'S MAP OF THE WORLD This world map by the ancient geographer Strabo (c 63 B. C. to 21 A . D.) came into Portuguese hands via the Eastern church delegation to the famous Council of Florence in 1439. The map shows that the ancients clearly knew it was possible to circumnavigate A frica. Herodotus gave a famous account of such a voyage, but a redrawing by Claudius Ptolemy (90 to 168 A . D.) had led to the belief that this was impossible. Vasco da Gama's 1497 voyage to India proved the truth again.

Source: Reconstruction based on E.H. Sunbury's A History of Ancient Geogrephy. London. t879

voyage to India in 1497. By then Bartolomeo Dias had reached the Cape of Good Hope the hard way-on a route paral lel ing the African coast, which took five months to complete. Rounding the Cape and sai l ing on to India by this method could be expected to take as much as five months more : The total requi rements were beyond the technological capacities of the caravels.

What Da Gama did-after a decade of intense Portuguese researches into the wind and ocean currents of the South Atlantic-was to sai l with the prevai l ing winds and cu rrents down to the latitude of the Cape Verde Islands (about 1 50 N) uti l izing the generally clockwise circu lation of wind and ocean in the northern hemisphere. He then cut across the equatorial doldrums, to intersect the mi rroring counter­clockwise circulation in the southern hemisphere and fol­low it southwestward, almost to the coast of South America. (Pedro Alvares Cabral , in the next voyage, would officially "d iscover" Braz i l by exactly this Long Ocean Tack-a dis­covery almost certain ly made earlier by the crews doing the reconnoitering for the breakthrough) . Once in the " roaring 4Os" past the southern Horse Latitudes, Da Gama " hitch­h iked" a ride back eastward to intersect the African coast at almost precisely the Cape of Good Hope.

It was a route that was not to be improved upon in the next 400 years, and although for Da Gama it involved being out of sight of land for over three months and 3,800 mi les (compared to Columbus's 33 days and 2,000 mi les on his

26 Summer 1 992 21 st CENTURY

famous voyage five years earlier), it cut the time of the passage in half. I t was a staggering feat of seamanship.

Columbus'S masterly use of the circulatory pattern of the nort hern belt for his voyage (out on the Trades, back in a northerly route intersecting the Azores), shows how well he had learned the Portuguese method of the " Long Ocean Tack ."

The Revolution in Navigational Astronomy Coupled with the revolutions in shipbui lding and the use

of wi nds and cu rrents accompl ished by the School of Sag res was a revolution in navigational astronomy. The pole star had long served mariners as a rough guide for determining latitude. The angle of the pole star above the horizon is, with minor modifications, identical to one's latitude. How­ever, the needs for measu ring instruments, charts, and ta­bles had been minimal because voyages took place within a relatively narrow belt of latitudes and usually had visual landmarks within several days of sai l ing to correct any er­rors. The long distances out of sight of land introduced by Henry's navigators forced the Portuguese to bring the astronomical knowledge and inst ruments of court astrono­mers within the reach of the common sai lors-heretofore considered too lowly to merit access to them .

Thus, in the last years before Henry's death in 1460, we find the first consistent mention of use of the quadrant, an instrument for sighting the Sun or stars, on board the

The Lisbon shipyards in a detail from a 16th century German engraving. By the end of the 15th century, the center for Portuguese exploration had moved from Sagres to the capital, Lisbon.

Portuguese caravels. Within 20 years, the astrolabe, an in­strument of Arab design for f inding star positions, came into common use, after design modifications and simplifi ­cations carried out by the successor to Henry's School of Sagres, the Junta dos Matematicos in the Lisbon cou rt . (Co­lumbus carried both instruments) .

Extensive correlations of latitude-sighting with cities and landmarks along the coast of Africa and Europe were sent out with each succeed ing voyage, along with the detailed accumulated sai l ing gu ides of all the previous voyages.

But a problem of an entirely different order was soon to present itself to the Portuguese. As they neared and then crossed the Equator in the years 1454-1474, they saw that the pole star rode lower and lower on the horizon, unti l it finally disappeared . Yet there was no southern hemisphere equivalent for the pole star. A navigational guide to deter­mine latitude below the Equator was requ i red.

Based upon centuries of accumulated knowledge of solar declinations, a new navigational manual was developed, the Regimento do Astrolabio e do Quadrante. This great collaborative effort of two Jewish astronomer-mathemati­cians, Abraham Zacuto and Jose Vizinho, was ci rcu lating in manuscript form at precisely the time Columbus was preparing to head west. It was the first bona fide practical

navigational manual . "So fundamental is this excessively scarce l i tt le volume that all later treatises on navigation, even to the present day, may simply be regarded as revised and enlarged ed itions of the original Regimento, " Penrose writes .

East or WesH Our examination of Henry's project has brought us to

the point of the "Moon Landings" of the 1 5th century : the successful passage to India by Vasco Da Gama in 1497-1499, and Columbus's voyage to America in 1492.

The conventional story is that Columbus, resident in Por­tugal in the early 1480s, sought Portuguese backing for his attempt to find the I ndies by a westward course, only to be foolishly turned down by King Joao I I and his cou rt experts, who thought the venture too rash and Columbus'S calcula­tions of the distances fau lty.

Another myth to be discarded. From the very beginning, Henry's efforts were dedicated

to "making the seas navigable , " not just pioneering a spe­cific route to the I ndies around Africa. From 1415-1497, more than 100 exploratory voyages went out from Portugal under the guiding hand of Henry and his successors. The idea of a western route had been very active in Prince Hen-

21 st CENTURY Summer 1992 27

ry's mind from the fi rst . Diogo Gomes, one of his great captains of the 1450s, d ictated the fol lowing description of how Henry's ships discovered the Azores in 1 432 :

As Prince Henry wanted to learn more about the remoter parts of the Western Ocean in order to see whether there were islands or a main land outside Ptol­emy's world, he sent out caravels at a certain time to look for land. They sailed away and found land [the Azores] 300 hours out from Finisterre [emphasis added] .

There i s faSCinating evidence that the F lorentine mathe­matician-astronomer Toscanel l i was u rging the Portuguese in the 1450s to head both south (circumnavigating Africa) andwest, to reach the I ndies. But in the last years of Henry's l i fe, and for the next 15 years thereafter, Portugal's interest in the western route waned as their caravels pushed farther and farther eastward along the Guinea and Benin coast of Africa, and their joyous surmise was that I ndia itself was just a l ittle ahead .

Then, in 1 474, came the crushing shock that after Ben in, the coastl ine of Africa turned south again and in relentless, unbroken fash ion. I nstantaneously the "western question" was revived . The canon of the Portuguese cou rt , Fernao Mart ins, exchanged correspondence with Florence's Tos­canel l i-the same Toscanel l i brought into contact with Por­tugal's enterprise back in 1 428-and sought h is advice on the feasibi l i ty and a route to head west. Martins had spent a large portion of the preceding 20 years in I taly, in a collab­oration with Toscanel l i and Cardinal Nicholas of Cusa. By 1480, Columbus was brought into this correspondence and the F lorentine Toscanell i addresses Columbus as "Portu­guese ."

At exactly the same moment, the Portuguese opened up a series of reconnaissance missions westward . On one of these, most probably in 1 476, Portuguese explorer Joao Vaz Corte-Real reached Labrador as part of a Portuguese­Danish expedition . Another is indicated by a 1484 royal license from King Joao I I stat ing:

Let al l who read this know that it is Our pleasure that Fernao Domingues de Arco, who lives on the island of Madeira, shal l , if he discovers the is land which he is now setting out to f ind, be made Governor of this said island.

Again, in 1486, court records show l icensing of an effort to "discover a large island, or many islands, or a mainland, " to the west, est imating that the passage should be given 40 days before being abandoned i f no land were sighted . The time frame eerily anticipates the 33 days it took Columbus to make the passage.

But then, in 1488, Bartolomeo Dias brings Joao the breathtaking news that he has rounded Africa at the Cape of Good Hope. Three years later, a reconnaissance team sent into Moslem areas of the I ndian Ocean reports details of the eastern coast of Africa, which el iminate the last terra incognita of the route. The decision was made to put their primary thrust into the assured route now open around Africa, but that did not mean that the feasibi l ity of sai l ing

28 Summer 1 992 2 1 st CENTURY

westward was doubted .

Columbus and Portugal Columbus had fi rst come to Portugal as a shipwrecked

mariner in 1 476. He married the daughter of the first settler­governor of Madei ra, whom Hen ry had sent out to the island in the early 1420s, and from his father-in-law he inher­ited a large archive of papers and observations . In 1482, after a series of other voyages on Portuguese ships, he sailed to the newly open ing frontier of Portuguese settle­ment and exploration, the Guinea Coast, and to the just­constructed Fort of Sao Jorge da Mina. A later notation of Columbus is history's best source of information on a trip by the great astronomer of Joao's Junta dos Matematicos, Jose Vizinho, to the Guinea coast to personally verify the groundbreaking new solar decl ination tables and rules he had helped prepare.

Columbus was thus in the middle of Portugal's marit ime breakout, at its densest moment of combined scientific and navigational expansion, when the route west was as seri­ously considered as the route south and east.

I t is fortunate indeed for history that a man of Columbus's determination and strength, energized by direct contact with the F lorentine scientist Toscanel l i and backed by the parallel Christian Renaissance currents and greater re­sources of Spain, stepped forward to take the "road not taken" by the Portuguese. Thus did Columbus ensure that Prince Henry's project " to prove devotion to God by mak­ing the seas navigable" brought the Renaissance Christian world simultaneously to the American continent and, by the Africa route, to the Indies.

Camoes, the poet lau reate writing the epic of Portugal's maritime expansion at its ebb 70 years later, su mmarized the fruits of Henry's great project in three beautiful l i nes of his Lusiads:

Por mares nunca dantes navegados (Canto I, 1 ) Novos mundos ao mundo i rao mostrando ( I I , 45) E se mais mundo houvera la chegara (VI I , 14)

"Through seas never before navigated , they will go on showing new worlds to the world. And if there were more to the world , they would arrive there."

Timothy Rush, a lifelong student of /bero-American af­fairs, is an active member of the Ibero-American Solidarity Movement. He has traveled widely in South America. This is an expanded version of an article which first appeared in Fidelio, Journal of Poetry, Science, and Statecraft, Spring 1 992.

References'--------------

Costa Brochado, et aI., 1 960. [)om Henrique the Navigator (lisbon). John Dos Passos, 1 969. The Portugal Story (Garden City, New York: Doubleday

and Co.). Paul Greenberg. 1 990. 'Roger Bacon and the Birth of Universal Science,' 2 1st

Century (Jan.-Feb.), p. 32. Bjorn landstrom, 1 964. The Quest for India (london: Allen and Unwin). Boies Penrose, 1 952. Travel and Discovery in the Renaissance (Cambridge,

Mass. : Harvard University Press) Paolo Emilio Taviani, 1 985. Christopher Columbus: The Grand Design (lon­

don: Orbis). Gustavo Uzielli, 1 892. 'Paolo Toscanelli, Amerigo Vespucci and the discovery

of America' (English translation by Richard Sanders, 1 99 1 , unpublished manuscript).